1. Field of the Invention
The present invention relates to a reclining mechanism for a vehicle seat for adjusting an inclined angle of a back rest of the seat relative to a seat cushion.
2. Description of the Prior Art
Disclosed in Japanese Patent Laid-open Publication No. 8-52040 is a reclining mechanism for a vehicle seat which is composed of a pair of arm members for attachment to a frame structure of a seat cushion and to a frame structure of a back rest, the arm members being connected by means of a hinge pin for relative rotation about the hinge pin, a slide pawl slidably coupled with one the arm members to be moved in a radial direction with respect to the hinge pin for engagement with a ratchet portion of the other of the arm members and for disengagement from the ratchet portion, and a cam element mounted on the hinge pin for rotation therewith and engaged with the slide pawl for maintaining the slide pawl in engagement with the ratchet portion of the arm member and for disengaging the slide pawl from the ratchet portion when it is rotated with the hinge pin. In the reclining mechanism, the relative rotation of the arm members is restricted by engagement of the slide pawl with the ratchet portion to lock the back rest at an inclined angle and is permitted by disengagement of the slide pawl from the ratchet portion for adjustment of the inclined angle of the back rest.
In the reclining mechanism, the engagement of the slide pawl with the ratchet portion of the arm member is maintained in a condition where the slide pawl is pressed by engagement with a portion of the cam element. When the cam element is rotated with the hinge pin to disengage the slide pawl from the ratchet portion of the arm member, the slide pawl is retracted by engagement with a portion of the cam element. If the reclining mechanism is applied with a heavy load, the slide pawl is slightly rotated due to an error in assembly of the component parts of the reclining mechanism. This results in looseness in engagement of the slide pawl with the ratchet portion of the arm member.